Method for increasing the conductivity of metals



S.-RUBEN METHOD FOR INCREASING THE CONDUCTIVITY OF METALS Sept. 4, 1928. 1,683,209

Original Filed Feb. 15, 1926 Qvwmtoz \SAHUEL RUBEN 3513' his 61mm; -W

Patented Sept. 4, 1928.

. 1,683,209 UNITED STATES PATENT OFFICE.

SAMUEL RUBEN, on NEW YO K. N. Y.

METHOD FOR INCREASING THE CONDUCTIVITY OF METALS.

Application filed February 15, 1926, Serial No. 88,433. Renewed-May 12, 1927.

This invention relates to a method for increasing the conductivity of metals and more particularly, it relates to a method for treat ing metals to increase their electrical con- 5 ductivity by controlling their crystalline structure and arrangement.

The object of the invention is to provide a means by which to permanently raise the conductivity of; metals at low cost.

) It has been demonstrated by many experimenters that metals are conductive according to their respective molecular characteristics and crystalline structure and arrangement. It has been shown that the conditions i of heating and cooling 2. metal determine the type and arrangement of crystals formed, especially as to size; the more quickly cooled, after rearrangement due to heating, the smaller the crystals and the less the symmetry of their arrangement; and, conversely, the more deliberate the cooling under like conditions, the larger the crystals and the 'more symmetrical their arrangement.

A copper body can be produced with a structure very close to a single crystal','the structures then having a symmetrical distribution throughout the body, and its conductivity is at. a maximum. In some instances such a structure shows thermal and electrical conductivity equal-to that of silver. It also has been demonstrated that the influence of a magnetic field upon the arrangement of crystals is directional.

Illustrative of the-tendency for crystal rearrangement through the formation of larger crystals and their alignment under the discharge of current is the behavior of tantalum when operated as a filament at incandescence. Operated on adirect current,

it has a relatively long life; but when alternatingcurrent is dischar ed, the life of the filament is very short. xamination of the structure shows, in the first'case, the formation of large crystals with the crystals sym-- metrically arranged and the long axes of the crystals lying in the direction of the current discharge, while in the latter case, the crystals are'much smaller and crystal arrangement is not orderly. A further example of the efie ct of the arrangement of crystalsupon' metal conductivityis that of iron in a magnetic field; The magnetic conductivity of this material decreasesand the electrical resistance increases with the temperature applied, until .a point of recale'scence is attained ,when the symmetrical arrangement is lost and the electrical resistance rises to a markeddegree.

Various means have been devised by which the crystalarrangement of metals may be controlled and permanently fixed; but the processes of the prior art have been too costly for practicable application.

Broadly, my invention'comprises a method for the formation of crystals which are larger than by their normal arrangement and arranging the crystals with their long axes in the direction of current discharge,

by heating and slowly cooling the metal in a non-oxidizing atmosphere in an electromagnetic field. referably by discharging a d1- rect current through a metal, it is heated below to its'melting point in a non-oxidizing atmosphere, such as hydrogen,- in an.electro'= magnetic field. The reaction between the external electromagnetic field and the in ternal field produces a redistribution of the crystals and efiects the formation of relatively large crystals, having their long axes parallel to the direction of the electromag-v netic field. and to the current discharge. This formation is permanent, due to the discharging of current through the metal when it is in a somewhat coalescent state in an atmosphere in which oxidation can not oc.-. our, and to the slow cooling under like field and atmosphere conditions, thereby holding that structure andarrangement until a point is reached at which further rearrangement of crystals can not take place. By the regulation of the current discharge, thedensity of the electromagnetic field and the rate of cooling, the degree of conductivity can be closely controlled. 7 i

For the purpose of a better understanding of the invention and its application, referslice is made-to the accompanying drawing which schematically represents one embodlment of the invention, in which 5 is a copper wire being treated by 'my process in furnace 6, containing hydrogen gas, for increasing its conductivity. The wire is being drawn from reel 1, through an electromagnetic field established by current discharged from generator G through coil 3, the same source of energy also heating the Wire 5, through rgoller contacts 2, 2 and 2,,. At 4,

is a resistance so th'a t less heating energy can be applied to the wire between contacts 2 and 2 than between. 2 and 2... As wire 5 passes between contacts 2 and 2 it is heated in an atmosphere of hydrogen to a dellu gree of temperature atwhich the crystals may assume a new arrangement which,

underthe influence of the current discharge and the electromagnetic field, realigirsymmetrically in larger crystals which become so placed that their long axes are parallel with the direction of current discharge and 'the electromagnetic field. As the wire pro gresses, less and less heat is applied, andthen it is permitted to slowly cool inits progress, still Within the electromagnetic field, until when it has: passed beyond the of. recalesence.

strong influence of the field, it has cooled to a degree at whichthe crystals are definitely set and no further rearrangement can take place until it may again be brought to a state this area of treatment its conductivity is much greater than when treatment was begun. The wire is drawn through and beyond the container by means of rollers I and 8.

2. The method of increasing the conduc-' tivity of a metal body which consists in heating said .body to a temperature below its melting point, by a current discharge therethrough, in an electromagnetic field parallel to the direction of said discharge,

' and cooling said body in an electromagnetic field until the crystalline formation of said body established by said treatment, becomes fixed. I i

3. The method of increasing the conductiv,ity of a metal body which consists in changing the arrangement of the crystal formation of said body by heating said body by the dischargeofan electric current there- As the wire emerges from through, to a temperature below the melting point of said body, in a magnetic field parallel to the direction of said discharge, and lowering the temperature of said body in an electromagnetic 'field, until said rear point by an electric current discharge therethrough in an electromagnetic field parallel to the direction ofsaid discharge, and cooling said body in a non-oxidizing atmos phere in an electromagnetic field parallel to the direction of said discharge.

5. The method of increasing the conductivity of a metal body which consists in heating said body in a non-oxidizing atmosphere to a temperature below its melting point, by a current discharge therethrough, in an electromagnetic field parallel to the direction of said discharge, and cooling said body in. a non-oxidizing atmosphere in an electromagnetic field until the crystalline formation of said body established by said treatment becomes fixed.

6. The method of increasing the conductivity of a, metal body which consists in changing the arrangement of the crystals into larger crystals and in a fixed position by heating said body in a non-oxidizing atmosphere by the discharge of an electric current therethrough, to a temperature below the melting point of said body, in a magnetic field parallel to the direction of said discharge, and thereby arranging the long axes of the crystals parallel to the direction of said discharge and lowering the temperature of said body in a non-oxidizing atmosphere in an electromagnetic field until said rearrangement of said molecules becomes fixed.

Signed at New York, in the county of New York and State of New York, this 13th day of February, A. D. 1926.

' SAMUEL RUBEN. 

